1. Field of the Invention
This invention relates generally to a color television camera, and more particularly to a color television camera having a single image pickup device.
2. Description of the Prior Art
Various color television cameras which use a single image pickup tube have been proposed up to now. Since both chrominance and luminance signals are obtained from the single pickup tube in such color television cameras, the band of the luminance signal is limited. For this reason, the reproduced image based upon a video signal from the previously proposed television camera has less than the desired sharpness.
Further, prior art color television cameras have employed a color filter made up of a plurality of different color stripes so that, if a chrominance signal obtained therefrom is detected, a narrow band luminance signal is produced from the detected chrominance signal. Since the photoelectric conversion characteristics of the image pickup tube of such color television camera or the input-output characteristics of the transmission circuit are non-linear, such non-linear characteristics cause a detection operation and, consequently, the chrominance signal is detected to produce a narrow band luminance signal which is superimposed on the inherent or desired luminance signal. The level of the described narrow band luminance signal is varied in accordance with the level of the chrominance signal or with the brightness of an object to be televised, so that non-uniformity appears in the level of the luminance signal which is finally obtained from the color television camera and hence a bright and dark pattern is formed in a picture reproduced from the output signal of the camera.